As brought out in co-owned U.S. Pat. No. 4,610,676, an important requirement for what are now commonly referred to as "two-piece" ostomy appliances is that their coupling rings be capable of flexing and deforming to conform with changes in the peristomal contour of a patient's body as that patient bends, twists, and moves about. It is also essential that such conformity be achieved without risk that the coupling rings will become unintentionally disconnected or that leakage of fluids (liquids or gases) might occur. Other considerations include ease of attachment and flatness of profile. The ideal coupling ring assembly should be flat enough so the fact that a patient is wearing an ostomy appliance beneath his/her clothing is virtually undetectable.
Ostomy appliances are known in which one coupling ring has an axially-facing annular channel and the other ring has a rib or projection insertable therein. Reference may be had to U.S. Pat. No. 4,460,363 and the patents cited in it. U.S. Pat. No. Re. 28,969 reveals that interlocking elements, one being channel-shaped and the other having a rib or projection receivable in the channel, have also been used to connect plastic films together along linear zones of attachment, and other patents such as U.S. Pat. Nos. 2,752,972 and 3,977,563 disclose similar interlocking arrangements used for replaceable container lids. Additional patents representative of the prior art are U.S. Pat. Nos. 2,994,117, 2,823,720, 2,144,755, and 2,581,604.
While two-piece ostomy appliances with coupling rings of various constructions have been known and used features included to meet certain of the requirements discussed above often reduce the capability of the appliances to meet other such requirements. For example, increased security of attachment might be achieved at the expense of reduced flexibility. Accordingly, it is an object of this invention to provide a coupling ring construction that results in a secure interconnection between the parts--one that resists fluid leakage as well as unintentional detachment--and, at the same time, is relatively flat, compact, and flexible.
The coupling rings of this invention are formed of flexible plastic material with the wall of each ring being generally C-shaped when viewed in radial cross-section. In coupled condition, one ring, which may be referred to as the inner ring, is nested within the channel of the other ring (the outer ring). The walls of the inner and outer rings have their opposing surfaces sealingly engaging each other; however, the sealing contact is along circumferentially-extending zones of contact with circumferentially-extending fluid-isolating reservoirs therebetween. Because of the reduced areas of surface contact, greater unit pressure and improved sealing effectiveness are achieved. Of particular importance is the fact that any fluid entering one of the reservoirs tends to become entrapped therein, with migration permitted in circumferential directions rather than axial directions. As a result, the coupling ring assembly is notably resistant to fluid leakage despite the ease with which it may be flexed or deformed.
Other features, advantages, and objects of the invention will become apparent from the specification and drawings.